1. Field of the Invention
The present invention relates to pivoted blade barrel rotor wind turbines, and more particularly to pivoted blade barrel rotor wind turbines which operate at high wind power extraction efficiencies at blade speeds near the wind speed and thus are capable of operating well over a wide range of wind speeds at a constant rate of rotation.
2. Description of the Prior Art
Pivoted blade barrel rotor wind turbines have been proposed in the prior art. The proposed pivoted blade barrel rotor wind turbines of the prior art have generally fallen into one of two categories, viz., (1) large scale, complex devices which involve elaborate electrical or electronic control systems and do not teach how to achieve high wind power extraction efficiencies in small scale plants suited to individual farm, ranch, home, housing development, or apartment complex applications, especially where freedom from the cost and maintenance problems of electrical or electronic control systems is a principal design criterion, and (2) small scale, all-mechanical devices for individual farm, etc., use, which have not achieved or closely approached maximum wind power extraction efficiencies.
Other recent prior art wind turbine proposals and developments have involved techniques easily adapted from hardware developed in the aircraft and aerospace industries and have been generally characterized by the use of high speed, narrow, highly stressed rotors which can be expected to give rise to continuing high maintenance costs and other problems of the type met in helicopter operation. These recent prior art wind turbine proposals and developments do not appear to hold promise for solving the problem of obtaining maximum wind energy extraction in conditions of high wind shear and strong turbulence, nor showing to what extent it is useful to harness wind energy at sites where the prevailing wind velocities do not generally exceed 20 knots.